The Research And Application Of Anti-whirl PDC Core Bits

Core bit is key tool of drilling formation to catch cores, and the quality of core bit will affect directly the core quality,core recovery rate and operation cost。The technical level of local PDC core bits has a big margin than the abroad advanced leve, the reason may be short of scientific design theory and method besides the low quality of cutting materials。This paper analyses the relations between the boren force of PDC cutters with rock formation,back-dip angle,cutting area and arc length,set up a boren force model of PDC core bit while coring;At the same time the paper studies and researches the method to design crown structure of PDC core bit,the arrangement of the cutter,down-hole fluid field analysis;Based on above research,establish a set of method to design anti-whirl PDC core bit which centres on force balance。New three sorts of PDC core bits have good effect on ground tests which have fast core penetrate rate and over 95% core recovery,Now these bits are applied disseminated in oil fields which obtains more economic benefit and social benefit。...